Best time to evacuate before a forecasted flood?

Understanding Flood Forecasting

Flood forecasting is an art that combines historical data, weather patterns, and mathematical models to predict water levels and flow rates. When a flood is forecasted, officials will typically provide a “forecast window” - the period during which the floodwaters are expected to rise and peak. This window can range from hours to days, depending on the severity of the flood and the speed of the water flow.

Preparing for Evacuation

To minimize risk, evacuate at least 12-24 hours before the floodwaters are expected to rise. This allows you to avoid the chaos and congestion that typically accompany a flood, as well as to reach higher ground before the waters become too deep. When preparing to evacuate, gather essential items such as non-perishable food, water, first aid supplies, and a change of clothing. It’s also essential to fill up your vehicle’s gas tank, in case you need to drive to higher ground.

Safe Evacuation Techniques

When evacuating, always choose the highest route possible, as floodwaters can be deceptively deep and swift. Avoid driving through flooded areas, as this can cause your vehicle to become trapped or swept away. Instead, use a vehicle’s four-wheel drive or high ground clearance to navigate through shallow waters. If you must wade through floodwaters, wear a life jacket and stay close to a stable object, such as a tree or a building.